Use output of subprocesses to collect statistics from certain format

Signed-off-by: Imran M Yousuf <imyousuf@newscred.com>
Support bash scripts in addition shell scripts

Also add support for being able to pass arguments to the command that we
are executing, i.e., each space in the configuration would be separator for
argument. We support URL (un)quote to support special characters

Signed-off-by: Imran M Yousuf <imyousuf@newscred.com>